It was a good setup 20 years ago. Nowadays with 1000W heads weighting less and talking less room than dedicated rack preamps, I don't really see the point.
I use separate pedal preamps though, with active cabs.

Pre/power gives the flexibility to change the voicebox of the system with a smaller level of investment, and also allows combining or alternating between different preamps. The downside is that not every good amp is represented as a stand-alone preamp, so there are fewer choices.

Crown makes fine power amps, as do a few other popular brands. In some rare cases there won’t be a good pairing between the signal output level of the preamp and power amp, so I am a big fan of using a line mixer between the two to allow for finer control of the interaction. It also allows for extensibility and the aforementioned blending.

I've run my Sansamp BDDI pedal directly into my power amp numerous times with great success. A pedal/power amp setup will depend a lot on the pedals output though. The BDDI has a +10 db button and with it pressed it sends a nice hot signal to my power amp.

It is important to match the pre-amp and power amp in terms of input/output impedance and input/output voltage. For example, if the power amp expects a certain voltage to make max power and the pre-amp can't output that voltage, you will not get the full power out of the power amp.

There is more to know about this (and I don't know more) so I hope someone will jump and maybe give a good reference source so we can all learn more.

I’ve been using a pre/power system of one sort or another since the late Sixties. It can offer the best of both worlds. Currently Carvin are the backbone of all my stuff. I recommend their equipment without reservation!

I’ve been using a pre/power system of one sort or another since the late Sixties. It can offer the best of both worlds. Currently Carvin are the backbone of all my stuff. I recommend their equipment without reservation!

I built my rack around the wonderful Fender TBP-1 preamp. Got a Crown 2500 XLS on here, and just added an Art power supply (thanks, Bassflute). I'm really enjoying the full warm sound of this rig, and don't see myself going back to an integrated bass head.

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I built my rack around the wonderful Fender TBP-1 preamp. Got a Crown 2500 XLS on here, and just added an Art power supply (thanks, Bassflute). I'm really enjoying the full warm sound of this rig, and don't see myself going back to an integrated bass head.

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Nice. I was thinking about the Fender pre. And I was looking at that amp.

I'm currently using the Mesa D-800+ into 2 GK 410's. Both cabs are rated at 800 RMS each. So I don't need to dip down to 2 ohms at this time. Don't really need tubes either. But it's a thought.

I was thinking of either a Sansamp, Mesa or GK pre pedal. The Alembic pre is a little pricey.

By the way, both my cabs are 8ohms each.

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Do you like the sound of your Subway, and if not, what are you looking for? The Mesa preamp is the pre that you already have in that head, except for some minor extra features in your plus model.

As for other preamps, why not just get one and try running it in your head's poweramp. The Tech 21 products for example are cost effective, offer ampegy sounds and can also be used as pedals into your existing pre.